Proposed Hysteresis Controller Research Articles

Performing reactive power compensation of three-phase induction motor by using parallel active power filter

Nowadays, the problem of power quality increases day by day. Harmonic current and reactive power are the important factors disturbing the power quality. The induction motors draw both harmonic current and reactive power from the grid. Reactive power and harmonic current lead to heat losses and decrease in the efficiency of the transmission lines. Passive and active filter applications have been used to solve these problems. There are some disadvantages of passive filters. Large physical dimensions and resonance with load can be shown as examples for these disadvantages. Therefore, the application areas of Active Power Filter (APF) are rapidly developing due to the fact that they can be applied together with harmonic and reactive power compensation as appropriate control methods. This paper proposes a MATLAB/Simulink simulation to perform power factor correction and reactive power compensation of three-phase induction motor by using three-phase Parallel Active Power Filter (PAPF). In order to generate PAPF’s reference currents the Sine Multiplication Technique (SMT) is used. Simulation studies are presented to be able to assess the performances under different motor operating conditions. The proposed hysteresis controller based PAPF filter makes the power factor up to 1 and the reactive power compensation of the three-phase induction motor.

Wideband Hybrid Envelope Tracking Modulator With Hysteretic-Controlled Three-Level Switching Converter and Slew-Rate Enhanced Linear Amplifier

A wideband hybrid Envelope tracking (ET) modulator utilizing a hysteretic-controlled three-level switching converter (3L-SWC) and a slew-rate enhanced linear amplifier (LA) are presented. In addition to smaller ripple and lower losses of 3L-SWCs, employing the proposed hysteresis control loop results in a higher speed loop and wider bandwidth converter, enabling over 80 MHz of switching frequency. A concurrent sensor circuit monitors and regulates the flying capacitor voltage $V_{\mathrm{ CF}}$ and eliminates the conventionally required calibration loop to control it. The hysteretic-controlled 3L-SWC provides a high percentage of power amplifier (PA) supply load current with lower ripple, reducing the LA high-frequency current and ripple cancellation current, improving the overall system efficiency. A slew-rate enhancement (SRE) circuit is employed in the LA, resulting in slew rate of over 307 V/ $\mu \text{s}$ and bandwidth of over 275 MHz for the LA. The SRE circuit provides a parallel auxiliary current path directly to the gate of the class-AB output stage transistors, speeding-up the charging or discharging of output without modifying the operating point of the remaining LA, while maintaining the quiescent current of the class-AB stage. The supply modulator is fabricated in a 65-nm CMOS process. The measurement results show the tracking of long-term evolution (LTE)-40-MHz envelope with 93% peak efficiency at 1-W output power, while the SRE is disabled. Enabling the SRE, it can track LTE-80-MHz envelope with peak efficiency of 91%.

Nearly Constant Switching Space Vector Based Hysteresis Controller for VSI Fed IM Drive

A constant switching frequency hysteresis controller based on current error space vector (CESV) for two-level voltage source inverter fed induction motor (IM) drive is proposed in this paper. Here the stator voltages along the α - and β -axes are estimated using current error information and steady-state model of IM. Estimated stator voltages, switching dwell times, and instantaneous voltage error vectors are used in the online hysteresis boundary computations. The steady-state CESV boundaries and the phase voltage normalized harmonic spectrum of the proposed hysteresis controller at different speeds resembles that of a constant switching frequency voltage-controlled bus clamping pulse-width modulation-based drive. The proposed controller exhibits adjacent voltage vector switching, fast dynamic response under transient conditions, and has a simple controller implementation. The superior performance of the proposed controller is simulated using MATLAB/Simulink platform and experimentally verified on a three-phase 2.2 kW IM drive.

A 67.1-ps FOM, 0.5-V-Hybrid Digital LDO With Asynchronous Feedforward Control Via Slope Detection and Synchronous PI With State-Based Hysteresis Clock Switching

We present a fully integrated digital low-drop-out regulator (LDO) with a 100-pF output capacitor ( ${C} _{\textbf {OUT}}$ ) in 65 nm, based on hybrid-synchronous-asynchronous control. The goal is to minimize both response and settling time for abrupt load changes, which in turn enables the ${C} _{\textbf {OUT}}$ scaling under a voltage droop constraint. The architecture is based on the synchronous proportional-integral feedback control in tandem with the asynchronous feedforward control. The asynchronous control loop employs load-event-based triggering , which compensates the output voltage immediately after a voltage droop, shortening response time. Then, the synchronous loop operates on either fast or slow clock selected automatically by a hysteresis control and quickly brings the output to the steady state, achieving short settling time. The proposed hysteresis control achieves superior stability and scales the lower bound of the slow-clock frequency by two orders over the existing scheme. The LDO prototype improves the response- and settling-time related metrics over the prior synchronous and asynchronous LDOs.

Eliminating short switching cycles when using hysteresis control of resistance spot welding systems

PurposeThis paper aims to present two hysteresis-control algorithms designed for medium-frequency, direct-current, resistance-spot-welding (MFDC RSW) systems. The first proposed control algorithm (MSCHC) eliminates the short switching cycles that can occur when using the existing hysteresis-control algorithms. This control minimises the number of switching cycles that are needed to generate the selected welding current. The welding-current ripple can be high when using this control algorithm. Therefore, a second algorithm (HCRR) is presented that reduces the welding-current ripple by half.Design/methodology/approachThe proposed hysteresis controllers consist of the transformer’s magnetic-flux-density hysteresis regulator and a welding-current hysteresis regulator. Therefore, the welding current must be measured and the saturation of the iron core must be detected. The proposed hysteresis controller supplies the inverter with the signals needed to generate the supply voltage for the RSW transformer, which then generates the selected welding current.FindingsThe proposed MSCHC algorithm produces the smallest possible number of switching cycles needed to generate the selected welding current. The high welding-current ripple can be reduced if the number of switching cycles is increased. The observed number of switching cycles and the welding-current ripple change if the welding resistance and/or inductance change.Originality/valueThe number of switching cycles can be minimised when using the first proposed control algorithm (MSCHC), and so the switching power losses can be minimised. If the welding-current ripple produced by the first control algorithm is unacceptable, the second control algorithm (HCRR) can reduce it by increasing the number of switching cycles.

Hysteresis Switching Control of the Ćuk Converter

Design details and analysis of the properties of a hysteresis switching controller for the Cuk converter are provided in this paper. The design is based on a switching control law which minimizes a common Lyapunov function derivative for the converter's continuous modes of operation. These continuous modes of operation are both marginally stable which causes some particularities in the design procedure. The design also meets the specifications in terms of the converter's duty ratio and the frequency limitations. The proposed hysteresis controller performance is analyzed with respect to the operating modes of the converter and illustrated with a number of representative and relevant simulations.

Online Computation of Hysteresis Boundary for Constant Switching Frequency Current-Error Space-Vector-Based Hysteresis Controller for VSI-Fed IM Drives

This paper proposes a current-error space-vector-based hysteresis controller with online computation of boundary for two-level inverter-fed induction motor (IM) drives. The proposed hysteresis controller has got all advantages of conventional current-error space-vector-based hysteresis controllers like quick transient response, simplicity, adjacent voltage vector switching, etc. Major advantage of the proposed controller-based voltage-source-inverters-fed drive is that phase voltage frequency spectrum produced is exactly similar to that of a constant switching frequency space-vector pulsewidth modulated (SVPWM) inverter. In this proposed hysteresis controller, stator voltages along α- and β-axes are estimated during zero and active voltage vector periods using current errors along α- and β-axes and steady-state model of IM. Online computation of hysteresis boundary is carried out using estimated stator voltages in the proposed hysteresis controller. The proposed scheme is simple and capable of taking inverter upto six-step-mode operation, if demanded by drive system. The proposed hysteresis-controller-based inverter-fed drive scheme is experimentally verified. The steady state and transient performance of the proposed scheme is extensively tested. The experimental results are giving constant frequency spectrum for phase voltage similar to that of constant frequency SVPWM inverter-fed drive.

SMES for Protection of Distributed Critical Loads

This paper proposes the use of a micro high-temperature superconducting magnetic energy storage system (HTS-SMES) to support critical industrial loads connected to the customer's 11 kV load bus with a ride-through capability of around 20 cycles. With the advances of power electronics and digital signal processing technology, such a system can also be utilized to improve the power quality of the power system. A novel control methodology is proposed to regulate the SMES discharge to extend the support time to critical loads during a short-term disturbance in the distribution network. Using a P-Q diagram, the analysis of the power flow from the energy storage system to the power system is presented. The proposed hysteresis controller with SMES increases the operating area in P-Q plane as compared to the conventional d-q controlled scheme used in the literature. This allows the system capability to be utilized to its maximum thermal limits. The scheme also has the capability to control the real and reactive power flow through the converter using the proposed hysteresis current control scheme. This provides the capability to optimize the available energy storage by using load priority scheduling. The detailed three-phase system simulation is carried out using realistic models of the power electronics components used in the converters. Laboratory test results on the prototype are presented to validate the proposed control scheme.